In his first-ever interview, the sole Australian survivor of the Waco siege has revealed to 60 Minutes what really took place during the 51-day stand-off, and why he believes crazed cult leader David Koresh will one day return to Earth as the son of God.

Brothers jailed for 'underworld rampage'

Farhad Qaumi, the widely feared gang leader of the Blacktown chapter of Brothers 4 Life, wanted to "take over Sydney".

But the 34-year-old is now likely to be in jail for life.

Qaumi has been sentenced to at least 43 years, and a maximum of 60, for his role in the fatal and "violent underworld rampage" that erupted in the city's west in late 2013 and the "cold-blooded" contract murder of debt collector Joseph Antoun.

His brothers Mumtaz, 32, and Jamil, 25, were also jailed on Friday for at least 36 years and 21 years respectively.

While sentencing the siblings in the NSW Supreme Court, Justice Peter Hamill said many people's lives had been affected by the trio's "outlandish and lawless violence".

"Two men are dead and it is pure good fortune that more people were not killed.

"Many people were exposed to the gangland and gun violence instigated by the offenders."